tingliangstu/sed

Spectral Energy Density analysis of phonon modes in 2D materials

Spectral Energy Density analysis of phonon modes in 2D materials

This code performs the Spectral Energy Density (SED) analysis of 2D materials using the trajectories from MD simulations as input. SED are calculated from the velocities in LAMMPS dump files.

The theory behind the method implemented here is the same as the one formulated by Thomas et. al.

This code was used to study the SED of phonon modes, their lifetime and mean free path, in Graphene/MoS2/Graphene van der Waals heterostructure. The results are published here

Dependencies

Numpy, scipy

dump.py from the Pizza tools for lammps must be placed in the path

Description of files

SED.py - the main code used to run the analysis

tauk.py - this module contains methods to perform lorentzian fit to the spectral energy density peaks

eigen.py - this module contains the class eigen with in-built methods to perform spectral energy decomposition

dump.py - module that comes with pizza

PowerSpectrum-HeatCapacity.py - code to compute the Heat Capacity

Restrictions

The atom IDs in the dump file must be sorted.

Input:

1. dump file containing velocity
2. mapping of atoms into the unit cells and basis positions
3. eigen vectors for the potential model used - can be computed using GULP

To do

Generalize code for dispersion along other symmetry lines (currently does only along gamma-M)

Citation

Please cite the following work if you use this code - Srilok Srinivasan, Ganesh Balasubramanian, Reduced Thermal Transport in the Graphene/MoS2/Graphene Heterostructure: A Comparison with Freestanding Monolayers,Langmuir 2018, 34, 10, 3326–3335. DOI - https://doi.org/10.1021/acs.langmuir.7b03974